A young father has suffered horrific burns, had both his arms amputated and is fighting for his life in hospital after suffering an electric shock on a scaffolding worksite in West Auckland.

A high voltage current ripped through Jahden Nelson's body as he dismantled scaffolding at a Massey property on Tuesday last week.

His mother, Toni Paikea, believes her 28-year-old son was holding a steel pole when it touched low-hanging overhead powerlines.

A neighbour who witnessed the accident heard a loud explosion, Paikea told the Herald.

Scaffolder Jahden Nelson, 28, is now in hospital after a worksite accident in Massey last week. Photo / Supplied

"The pole touched the powerline and she heard a big bang and saw a big fire ball go through under the scaffolding. Then [Nelson] collapsed. I don't know how many volts go through those lines. It was like an atomic bomb going off in his body. It went from one arm, through the other arm and straight down through his leg and thigh."

Nelson's cousin was working alongside him and cradled the unconscious man in his arms until paramedics arrived.

It's understood a second person was also injured.

Toni Paikea's son Jahden Nelson suffered an electric shock in a workplace accident in Massey last week. He is currently in ICU at Middlemore Hospital. Photo / Alex Burton

There are now questions about why the scaffolders were working beneath live wires and whether proper health and safety procedures had been followed.

Nelson — a devoted father of three preschoolers — suffered a heart attack and burns to 25-35 per cent of his body, as well as severe internal injuries, his mother said.

He was rushed to Auckland City Hospital for immediate surgery.

He has since been transferred to the burns unit at Middlemore Hospital and had extensive surgery to remove badly burned tissue and prevent infection. He is on dialysis and remains in a critical but stable condition in intensive care.

Paikea said she had to make the excruciating decision to have her son's badly damaged right arm amputated last week after being consulted by clinicians. His other arm was amputated a few days later.

"They've said it could be more [limbs]. I'm leaving that in God's hands. I just wouldn't wish this on anybody. It's the hardest thing a parent could go through. It's a life and death situation. I'm holding my son's heart in my hands."

Toni Paikea believes her son Jahden Nelson was holding a scaffolding pole at this Massey worksite which touched overhead wires. Photo / Supplied

Doctors say the next few weeks will be critical as to whether Nelson lives. If he does survive he could be in hospital for many months and face years of rehabilitation.

Paikea and Nelson's sister have been keeping vigil at the hospital since the accident, even sleeping in their car in the hospital car park.

She spent her first night at home since the accident yesterday — to collect clothing, "debrief and find composure".

Due to the risk of infection, only one visitor is permitted in his room at a time. Nelson's former partner and "baby mama" is alternating with Paikea at her son's bedside.

Paikea said the family had been flooded with messages of support from loved ones, some of whom had provided food and were also sleeping in cars at the hospital "to show their love and gratitude for my son".

Jahden Nelson, 28, with his baby daughter. Nelson is fighting for his life in hospital after a workplace accident in West Auckland. Photo / Supplied

Lines company Vector has given the family a sympathy card and $1000 in fuel vouchers.

Paikea said her son was an experienced scaffolder who had worked in the industry since he was 16. He was extremely conscious of health and safety requirements.

She questioned why the power had not been disconnected to the overhead lines while workmen were onsite, an oversight that had cost her family dearly, she said.

"Because of my son's experience and because he's the fussiest person ever, I know his health and safety is paramount. In my heart I believe he would have thought those powerlines were switched off."

Paikea said her son's employer, Supercity Scaffolding, had offered to pay for a car park at Middlemore Hospital and give food vouchers.

Jahden Nelson, 28, was critically injured after being shocked by electricity at a scaffolding worksite in Massey, West Auckland last week. Photo / Hayden Woodward

"But he's fighting for his life. Nothing is going to help."

WorkSafe was investigating and planned to put a drone up over the scene in coming days, Paikea said.

She understood several of her son's colleagues, including his cousin, had now quit their jobs.

Paikea thanked hospital staff for their "amazing" care and asked loved ones to pray for her son.

West Auckland scaffolder Jahden Nelson, 28, pictured with his baby daughter. Photo / Supplied

A Givealittle page has been set up to support the family.

Supercity Scaffolding could not be reached for comment. Vector told the Herald it was assisting WorkSafe and couldn't comment.

However, it confirmed a "close approach consent" was issued to the construction company to undertake work, "but while maintaining safe distances from the power lines".